Front matter defaults may not have worked for collection documents and posts due to a problem where they were looked up by their URL rather than their path relative to the site source

Configuration for the posts permalink might be borked when a user specified a value for collections.posts.permalink directly. This forced the use of permalink at the top level, which also affected pages. To configure a permalink just for posts, you can do so with:

collections:posts:output:truepermalink:/blog/:year/:title/

Both of these issues have been resolved. For more information, check out the full history.